Electrocatalytic nitrate reduction to ammonia by a triethanolamine Cu(II) complex

Herein, a trinuclear coper(II) complex [Cu 3 II (H 2 L 1 ) 2 (HCOO) 4 ], ( 1 ), stabilized by triethanolamine, H 3 L 1 , is isolated and characterized by various spectroscopic techniques and through single crystal X-ray structure. In the complex 1 , cooper(II) ions are in distorted octahedral coordination environment where two H 3 L 1 ligands and four formates are present to hold this tri-nuclear copper assembly. The complex 1 depicts as an efficient catalyst to produce ammonia (NH 3 ) through electrocatalytic nitrate reduction (eNO 3 RR) in a 0.2 M acetate buffer of pH 3, following a pseudo-first-order reaction kinetics producing 83% Faradaic Efficiency (FE%) of NH 3 at −0.3 V vs. RHE with a yield rate of 21.56 μmol h −1 cm −2 at −0.5 V vs. RHE by suppressing the competitive HER.